What Adhesive is Right for Your Mosaic Project

Before you begin your mosaic, it is essential to consider what adhesive you will use on your project. Use the wrong adhesive, and you risk your mosaic not lasting as long as it should.

The choice of adhesive is affected by several factors; the base you are using, the environment where the mosaic will sit, the materials/tiles you are using and whether the mosaic will be submerged in water.

To understand the best adhesive for your project, you need to understand the choices available and which works best with different surfaces and environments. Adhesives are rated for different uses; indoors, outdoors, vertical, horizontal and submersible. To achieve the result, you are after you need to select the right one for your application.

Adhesive Type	Description
PVA - Polyvinyl Acetate (also known as craft or wood glue). PVA adhesive (also known as ‘white craft glue) is commonly available and cost-effective. Suitable for indoor mosaics only, it dries reasonably quickly, is moderately water resistant, dries clear, is non-toxic and cleans up in water. PVA adhesives should not be used on any outdoor project. Weldbond is considered the best PVA adhesive by many mosaicists. We stock Sullivans PVA adhesive and use it in our mosaic kits. Go to Sullivans PVA Adhesive >>	Suited to the direct method of mosaics as tiles can be coated with glue before placement Non-load bearing can be used on mosaics that lie flat or have little weight bearing. Not waterproof making it not suitable for exterior applications Diluted, it can be used as a sealant in a ratio of 50:50 to water
Cement Based Adhesives They come in pre-mixed and powder form; the pre-mixed ones are generally not as strong as the ones you mix yourself. These adhesives are rated differently, suitable for horizontal, vertical or submerged water environments. Cement-based adhesives are referred to as ‘Thinset’ in many mosaic books. We stock a waterproof powered Cement Based adhesive that is mixed with water. Buy Now >>	It is suited for the indirect method of mosaics for making an adhesive bed. Work best for outdoor work, floor and heavy traffic areas. Best adhesive to use if using the direct method and uneven tesserae. Cement Based Adhesive can be applied like icing. Place in a plastic bag and cut a corner (just like an icing bag) It can be made waterproof by mixing it with an acrylic additive. Great for stepping-stones, birdbaths, terracotta and exterior mosaics. The bond between the tesserae and the backer material is improved by adding a commercial tile bonding agent and priming the backer material before applying the adhesive. Will hold your tiles when working on a curved surface; you can lay your tiles in a bed of cement-based adhesive.
Liquid Nails Manufactured by Selleys brand and available in a range of different adhesives for specific applications. Available in cartridge gun form, but some products are in smaller squeeze packets.	Clear Liquid nails are a handy adhesive in mosaics. Not only is it clear drying, but it is a tacky adhesive that holds heavier tiles in place while drying. It can be used to compensate for variations in thicknesses. Place a dollop onto a disposable sheet and use a tool to apply the adhesive to the mosaic. Do not use Clear Liquid Nails on mirror as it may lead to the mirror de-silvering Platinum Liquid Nails is an extremely strong adhesive but difficult to work with. Do not let the adhesive come into contact with your skin; use only in well-ventilated areas. Not for the faint-hearted!
Clear Silicone	Dries clear, so great for glass-on-glass projects Waterproof and flexible Suitable for use on mirror tiles as it won't de-silver the back Make sure the back of the tile is coated completely so that grout cannot seep under the edges and spoil the effect A tacky adhesive that allows heavier pieces to stay in place while drying Strong smelling, use in a well-ventilated room
Epoxy Resin These adhesives are very strong, have a noxious odour and are difficult to work with. They work well on non-porous surfaces such as metal and glass. They have a short working period, so they are unsuitable for beginners. If using this adhesive, ensure you are well prepared to work quickly.	Suitable for internal and external mosaic work It comes in two parts, a hardener & resin that are mixed just before use. Extremely strong adhesive It produces a lot of fumes and must be used in a well-ventilated space. Great for outdoor applications which are constantly wet (e.g. birdbaths) Can hold heavy tesserae pieces (e.g. Stones, Shells) It is the only adhesive that will permanently stick tesserae to metal. The adhesive can be tricky to work with; it is extremely sticky, runny, and usually set relatively fast. Not for beginners to mosaics.
Weldbond (PVA adhesive) We stock Weldbond Adhesive. Buy Now >>	Weldbond can be used on cement, concrete, bricks, plaster, metal, glass, wood and tiles Stronger than the average white craft glue Water soluble, no fumes, non-toxic and easy to clean up Dries clear, making it suitable to use on glass-on-glass applications Not waterproof making it not suitable for exterior applications Suited to Direct Method of mosaics as tiles can be coated with glue before placement Diluted, it can be used as a sealant; mix 4 or 5 parts to one with water for sealing wood and terra-cotta projects
Mastic	A very sticky, paste-like adhesive It has excellent slip resistance and works well for vertical surfaces. Applied with a craft stick or palette knife Not recommended for use on floors; under pressure, it can become brittle and break down Not recommended for exterior applications or in areas where moisture is present Not as strong as cement-based adhesives Used to attach the tile to drywall

Some handy tips:

Always follow manufacturers' instructions.
Choose an adhesive that is suitable for your chosen base or substrate.
Work in a well-ventilated area
Ask advice at your hardware store if you are uncertain about a particular adhesive.
Don't be tempted to apply too much adhesive; it will squeeze around the sides of the tile and may require clean-up work before grouting. There needs to be room around the sides of the tiles for grout.
As a rule of thumb, the adhesive should cover 25% up the side of the tile.
Masking or packaging tape can be helpful in temporarily supporting tiles while the adhesive dries.